Implantation of lenses (Phakic intraocular lenses, or PIOLs) inside normal or phakic eyes to correct vision, while retaining the ability to focus up close, has been gaining favor and popularity. Recent improvements in the quality of the IOL and the discovery by many patients that they do not qualify for laser surgery on the cornea [such as LASIK (laser-assisted in situ keratomileusis), LASEK (laser epithelial keratomileusis), or PRK (Photo Refractive Keratectomy)] mean that Phakic IOLs are increasingly in demand. In addition, it is becoming apparent that individuals qualified for both laser surgery and IOL implantation who require higher powers of correction are generally more satisfied with the Phakic IOL procedure, because it results in better quality of vision. One drawback to the Phakic IOL solution is the need for sutures to close a large incision in the cornea after implantation of a (nonfoldable) lens. Use of sutures is time-consuming and usually causes unavoidable astigmatism or blurry vision. It has been proven that a Z-stroke (Langerman) or multi-planar incision 1b in the cornea 1a (FIG. 1) creates an incision “flap” that, because of the eye's internal pressure, is self-sealing, eliminating the need for sutures. With currently available knife blades, incisions of this kind that are as much as 5-6 mm wide are successfully self-sealing (Koch, Shelton). However, current Phakic IOL implantation procedures necessitate larger 7-mm incisions. Using currently available instruments to create these larger incisions requires an inefficient process of making multiple strokes, and using multiple instruments, and the results have not yet been proven to be self-sealing.
At this time there are very few instruments designed to handle the larger-sized, (nonfoldable) Phakic IOLs, and no type of a device for injecting this type of lens or a variety of lens is available. Therefore, some new type of instrument is needed to create a large incision that is self-sealing, and then to place this lens into the eye more efficiently.
It has been proven that a Z-stroke (Langerman) or multi-planar incision 1b in the cornea 1a (FIG. 1) creates an incision “flap” that, because of the eye's internal pressure, is self-sealing, eliminating the need for sutures. With currently available knife blades, incisions of this kind that are as much as 5-6 mm wide are successfully self-sealing, Koch, Paul S., M.D. Converting to Phacoemulsification. Slack Inc., Thorofare, N.J., 1992, pp 3-29.
However, current Phakic IOL implantation procedures necessitate larger 7-mm incisions.
Current Surgical Procedure for Phakic IOLs (FIG. 2): About a week preoperatively, a (Nd:YAG) Laser Peripheral Iridotomy (LPI) is usually performed to make a small hole in the iris to prevent acute glaucoma, a sudden rise in pressure, when this type of IOL is inserted. Just prior to surgery, pilocarpine (4%) drops are instilled to constrict the pupil, and anesthesia is then given. Surgery begins by making a side-port incision into the cornea and injecting viscoelastic fluid into the anterior chamber to make the eye firmer, which aids in making better incisions. The surgeon then makes a 7.0-mm incision into the cornea, usually using two or more instruments such as a forceps, microsharp, keratome, and possibly scissors. Usually a lens glide 2a is manually placed inside the eye with forceps to serve as a guide for positioning the IOL 2b and to protect the natural lens and iris during placement (FIG. 2). The surgeon then uses forceps in one hand to grasp and lift the corneal flap and to give counter-traction, while manipulating another forceps in the other hand to insert the IOL into the anterior chamber. After removing the lens glide, the surgeon uses forceps to position the IOL under the corneal shelf and into the proper angle between the iris and the cornea. Finally, the anterior chamber is irrigated to remove the viscoelastic material, and sutures are placed to close the corneal incision. This, procedure depends upon the skill of the surgeon, but usually requires about 20 minutes, 20 percent of which may be spent in placing sutures to close that incision. The fact that astigmatism results from the use of sutures is nearly unavoidable (Koch). The source for this current procedure was www.oii-iol.com.
Wishinsky (U.S. Pat. No. 5,217,476) and Lager (U.S. Pat. No. 5,217,477) propose dual widths of a surgical knife to make two precise and separate incisions for the phaco tip (3.2 mm) to remove the cataract and then for the IOL (5.2 mm) to be inserted. In a similar concept but for different purposes, a less tapered blade with a steeply tapered and very short point form two widths (FIG. 4) but for the purpose of allowing the surgeon to make the single, much larger IOL incision (6-7 mm) more easily and may optionally make the small side port incision (1 mm) with just the tip.
Praeger (U.S. Pat. No. 4,676,792) noted that a ridged lens glide provides better control than a flat lens glide and allows better exposure to manipulate the lens than an envelope-type lens glide. A semi-rigid lens glide with a tip that is flat and flexible, and a base that has a rigid bottom and similar ridged sidewalls allows for similar exposure but for greater maneuverability of the IOL once inside the eye. This semi-rigid lens glide also forms a wedge to efficiently open the incision for the insertion of the IOL.
For the purpose of “wicking” out fluid from the eye to lower the pressure in glaucoma patients, Simon (U.S. Pat. Nos. 5,651,782 and 5,676,679) proposes a surgical knife with a wedged blade that makes an incision and inserts an artificial meshwork underneath the blade from behind the wedge. In a similar manner, a knife blade is wedge-shaped to open the incision on top to co-insert another instrument, the IOL Injector.
Rhein Medical, Inc. (US Patent RE37,304) describes a beveled blade of specified different taper on both faces where both sides or shoulders are slightly thicker than the center for the stated purpose of making an incision but not of any sufficient thickness or description to form a wedge for the intended purpose of co-inserting another device. The blades in this design may have different taper in the bevel to form a wedge, and/or may be thicker in the sides or shoulders for efficiency. However, these features are not essential to form a basic mechanical wedge involved in the present invention that functions to open the incision upward, allowing the insertion of the tip of the lens glide that lies in a “scooped-out valley” on the top of the blade and behind this wedge.